I would think that attendance is usually higher that you are all predicting on the 1st game of the season no matter who we play. Just like Opening Day in baseball. I will guess that attending will easily be in the 40s.
So ... 47,000+ announced for 2015 opener (Norfolk State) and 45,000+ announced for 2016 home opener (Howard). Season tickets were down by 8,700 between 2015 and 2017 and no no gain this season. So, you're starting with a base of something like 20,000 tickets sold now. Add in, maybe, 3-4,000 students for a noon start on a holiday weekend.
There are choice tickets on StubHub in 106-108 for $20 or sit upstairs for $7. Those would be our season ticket holders with family plans or allergic to a hot day in the sun.
Hobbs will never announce a "crowd" under 40,000, but he'll have to cut it close because the place is going to look only a little more than half full, even with 100s of freebies to youth football, etc.
Just win, baby!